Delete support for converting sage viewpoints.
Delete support for converting sage viewpoints.

Surprisingly, Sage's viewpoint support is very poor and unused.  Apparently Sage *always* has a viewpoint of (0,0,6), and is documented as being just a stub for x3d.
jasongrout/pythreejs,nlooije/pythreejs,nlooije/pythreejs,jasongrout/pythreejs,nlooije/pythreejs